FOCAL PORTA HEPATIS SCINTISCAN DEFECTS: WHAT IS THEIR SIGNIFICANCE? Robert R. McCleIIand University of Minnesota at St. Paul-Ramsey Hospital, St. Paul, Minnesota A total of 537 consecutive liver scintiscans reasons, a retrospective review of this hospital's ex were retrospectively reviewed and 80 of them perience regarding single, focal porta hepatic defects, revealed suspicious focal decreased activity in and their correlation with clinically significant find the region of the porta hepatis. Postmortem, ings, was undertaken. surgical, or biopsy correlation was obtained in 40 of these cases: 14 were pathologically nega. MATERIALS AND METHODS tive; 9, cirrhosis or fibrosis; 10, metastases; 3, dilated bile ducts; 1, viral hepatitis; 1, hepatic All liver scintiscans performed at St. Paul-Ramsey laceration; 1, falciform ligament cyst; and 1, Hospital during the period March 1, 1971 , to March ruptured gallbladder with abscessed head of the I , 1974, were evaluated for the presence of single pancreas. Thus, only 42% represented signifi focal decreased activity in the region of the porta cant disease. Sixty-eight percent of the defects hepatis. Scintiscans were evaluated- retrospectively were seen only on the anterior scintiscan. Ap by an experienced nuclear medicine physician with pearance of the majority of defects was non out the knowledge of clinical history or previous specific. Subjective grading of defects according interpretation. Marginal defects in the porta hepatis to size and comparative decrease in density was region were not considered. The clinical charts of not beneficial. Elevations of serum alkaline all patients with porta hepatis defects were then phosphatase, total serum bilirubin, and serum reviewed, and surgical and pathologic correlation glutamic-oxalacetic transaminase were nonspe was made when possible. Correlation was also made cl/ic. with serum alkaline phosphatase, total serum bili rubin, and serum glutamic-oxalacetic transaminase (SGOT) . The data were analyzed and grading ac Of the several types of nuclear medicine scinti cording to subjective interpretation of defect promi scanning procedures performed in a modern nuclear nence (size and comparative decrease in intensity) medicine department the liver scintiscan is certainly was attempted. Single focal hepatic defects were among the most difficult to interpret. This difficulty considered significant when they represented neo relates to limitations of equipment resolution; diffi plasm or surgical lesion. Single porta hepatis defects culty in portraying an area of decreased activity in caused by normal anatomic structures or cirrhotic or a large organ with prominent activity; numerous fibrotic changes were not considered significant. All developmental variations in configuration; superim liver scintiscans were performed with oomTc_sulfur posed or inherent anatomic structures, such as the colloid using either the Picker 5-in. rectilinear scan porta hepatis, gallbladder, hepatic veins, costal mar ner with a 3-in. focal length, ½-in. resolution colli gin, vertebrae; and nonspecificity of scintiscan de mator, and 14 X I7-in. film, or with the Searle fects (1,2) . Numerous authors have recommended Radiographics Pho/Gamma HP scintillation camera caution in interpretating marginal irregularities and with a high-sensitivity, parallel-hole collimator and single focal defects, especially -if these are located 70-mm film. All scintiscans included at least an an in the region of normal anatomic structures or are tenor and right lateral projection, and more recent # seen on only one scintiscan projection (1—3) . This author has not infrequently experienced the frustra tion of having called a scintiscan defect in the porta Received March 21, 1975; revision accepted May 5, 1975. For reprints contact: Robert R. McClelland, Dept. of hepatis anatomic or insignificant, only to find at Radiology, St. Paul-Ramsey Hospital, University at Jackson, surgery a significant lesion, and vice versa. For these St. Paul, Minn. 55101. Volume 16, Number 11 1007 MC CLELLAND TABLE 1. PATHOLOGIC CORRELATION OF 40 PORTA HEPATIS SCINTISCAN DEFECTS Ob- Percent Patho- structed signifi logically Cirrhosis dilated Viral Falci- Ruptured cant Subjective nega- or Metas- common hepa- Lacera- form gall- pathol grading tive fibrosis tases bile ducts titis tion cyst bladder Total ogy Gradel 8 3 2 2 15 27 Gradell 2 2 7 1 1 1 14 71 Gradelll 3 3 1 1 8 25 GradelV 1 1 1 3 33 Total 14 9 10 3 1 1 1 1 40 42 scintiscans performed with the camera included pos tenor projections. RESULTS Of the 537 consecutive hepatic scintiscans re viewed, 80 were considered to have significant or @ .(4@. questionably significant decreased activity in the region of the porta hepatis. Of these 80, 40 had post mortem, surgical, or biopsy data. Only the 40 scm tiscans that were correlated will be discussed in this paper. Table 1 lists the pertinent correlative findings of FIG. 1. Stonesobstructingcommonbileductcausingdilatation of ducts. Focal decreased activity in region of porta hepatis noted the 40 scintiscans discussed in this paper. only on this anterior scintiscanproiection. Note ill-defined bands Two of the three cases with dilated common bile of decreased activity extending from porta hepatis defect into ducts listed in Table 1 were caused by stones ob midportion of right lobe and inferior portion of left lobe of liver. structing the common bile duct at the ampulla (Fig. 1) , and one was caused by metastatic carcinoma of the head of the pancreas, which invaded the region of the ampulla and obstructed the common bile duct. Metastases in this study included blood-borne or lymphatic spread of neoplasm to the porta hepatis, as well as direct extension of tumor from adjacent structures. Figure 2 shows the scintiscan of a 67- R .@- I year-old male p@ient with carcinoma of the head of the pancreas, with extension of the tumor along lymphatics and invasion of the po@ta hepatis region. The one case of viral hepatitis (Fig. 3) occurred FIG.2. Ca.'@riaiaof headof pancreasinvadingportahepa in a 20-year-old jaundiced male. Pathologic correla tis. Focal decreased activity in region of porta hepatis noted only on this anterior scintiscanprojection. tion was not obtained but the patient did have a posi tive Australian antigen test. This patient recovered clinically, but a repeat liver scintiscan 3 months later R I revealed the same porta hepatis defect. Of particular interest was the case of an asymp tomatic 49-year-old female admitted with a non tender, crepitant, right-upper-quadrant mass (Fig. 4) . At surgery a large developmental cyst of the falciform ligament was found and excised without complication. The most striking scintiscan in this series occurred in a 70-year-old female with a palpable epigastric mass and slightly elevated liver function studies (Fig. FIG. 3. Viral hepatitis.Focaldecreasedactivityin the region 5 ) - Exploratory laparotomy and liver biopsy re of porta hepatis noted only on this anterior scintiscan. 1008 JOURNAL OF NUCLEAR MEDICINE DIAGNOSTICNUCLEAR MEDICINE R I A B B FIG.5. Cirrhosisandfocalscarring.(A)Anteriorscanshows large area of decreased activity in region of porta hepatis and hypertrophy of left lobe of liver. (B) Right lateral scan shows ver R tical band of decreased activity. TABLE 2. PATHOLOGIC CORRELATION OF 13 PORTA HEPATISSCINTISCANDEFECTS SEENON TWO PROJECTiONS Defect Number seen on two projections C Pathologicallynegative 3 Cirrhosisand/or fibrosis 3 Laceration 1 FIG.4. Anterior(A),rightlateral(B),andposterior(C)scinti Metastases 6 scansshowingfalciformligamentcyst.Focaldecreasedactivityin Total 13 region of porta hepatis is noted only on anterior scintiscandespite prominence of defect. vealed hypertrophied left lobe of the liver and ex DISCUSSION tensive scarring in the region of the porta hepatis. Anatomically, the porta hepatis is located at the Biopsy in this region revealed active portal cirrhosis inferior surface of the liver between the quadrate lobe with fatty metamorphosis and alcoholic hyaline. anteriorly and the caudate lobe posteriorly. From Of the 40 cases of porta hepatis scintiscan defects the posterior aspect, the porta hepatis lies between in this series only 13 defects were seen on two pro the right and left lobes of the liver and, from the jections of the scintiscan and these were all on the anterior aspect, it lies under the medial segment of anterior and right lateral scintiscans. No porta he the left lobe of the liver. In the anterior scintiscan, patis defects were detected on the posterior scinti the porta hepatis should lie to the left of a line drawn scans. Pathologic correlation of the 13 cases seen on vertically through the middle of the liver. In the two projections is shown in Table 2. anterior projection, the porta hepatis can cause a Table 3 shows correlation of pathologic findings marginal-type defect, but more frequently it lies with serum alkaline phosphatase, total serum bili several centimeters up from the inferior margin of rubin, and SGOT. the liver and appears as a vague area of decreased Volume 16, Number 11 1009 MC CLELLAND the porta hepatis to the pancreas, ampulla, and TABLE 3. CORRELATION OF PORTA HEPATIS gallbladder from which neoplasms can extend di FINDINGS WITH SERUM ALKALINE PHOSPHATASE, rectly. TOTAL SERUM BILIRUBIN, AND SGOT The three cases of dilated bile ducts in this series ElevatedserumElevatedNumberalkalinetotalofphos.serumElevatedTypesubstantiate the comments made by DeLand and Wagner, who stated, “Sincethe bile ducts may simu late metastatic lesions, even a clear-cut focal area casesphatasebilirubinSGOT of decreased activity in the region of the porta hepatis Pathologically should be interpreted with caution in patients with negative 14 2 0 5 obstructive jaundice―(6) . Two papers (8,9) have Cirrhosisor fibrosis 9 2 3 4 described a typical liver scan pattern for obstructed Metastases 10 6 3 5 biliary ducts, consisting of band-like areas of de Obstructed creased activity radiating from an area of decreased bileducts 3 3 3 3 Viral activity in the region of the porta hepatis similar to hepatitis 1 1 1 1 Fig. I . Both references recognized that false-positive Hepatic and false-negative results can occur.